DevTools failed to load SourceMap: Could not load content for http://localhost:19000/debugger-ui/ui.e31bb0bc.css.map: HTTP error: status code 500, net::ERR_HTTP_RESPONSE_CODE_FAILURE code example

Example: devtools failed to load sourcemap when debugging react native

Open Developer Tools, 
go to "Settings" for Developer Tools, 
then uncheck Enable JavaScript Sourcemaps under the "Sources" settings.
Restart Browser if needed